The present invention relates to the analysis of digital words to identify their source or content. These words may be part of a digital data stream, or they may be signatures consisting of a set of digital parameters measured on a signal or object. More particularly, the present invention relates to a method of and a system for analysis of multi-bit digital words to identify a pattern in the words, or to identify the signal or object on which the parameters represented by the words were measured.
Numerous systems operate by analyzing a received signal to identify the source of the signal. As one example, the entrance to a building or an industrial plant might be secured with a locking system which responds to receipt of a spoken request for admission by analyzing the received voice signal to ascertain whether the person making the request is authorized for admission. If the locking system determines that the person is authorized, then it responds by unlocking the entrance. As another example, a check sorting machine in a bank might include a sensor for scanning indicia printed on the checks to determine the identification numbers of checking accounts on which the checks are drawn. Such systems generate signatures indicative of the source of the signals. While such signatures can be identified by direct matching with known signals, matching of the signatures to known signals can be a complex undertaking, requiring considerable circuitry and electrical power and an undesirably long time. Locating any one of a number of names, numbers or other bit patterns in the digital data stream from a disk drive or communication link is an example of identifying a bit pattern directly.